For millennia, scientists and philosophers have strived to show that the universe is governed by a few simple principles. These principles are not derived from science. They do not come from looking through telescopes or carefully examining the results generated by particle colliders. Rather,they are based on aesthetic laws and concepts such as symmetry, beauty, and unity. Scientist and author David Orrell considers how aesthetics have influenced the models we create in hopes of explaining our universe. His book begins with a look at early scientific thinkers, from the ancient Greeks to Galileo. The ancients constructed a concept of the world based on musical harmony;later thinkers overturned this concept, but replaced it with a program, based on Newton's "rational mechanics," to reduce the universe to a few simple equations. Orrell then turns to the scientific program of the twentieth century, culminating in supersymmetric string theory, which was againinfluenced by deep aesthetic principles. In a final section of the book, Orrell broadens his discussion to other fields of research, including economics, architecture, and health. Recent history has shown us what happens when financiers rely on a model of economics that resembles what a good theory"should look like" rather than the messy reality of human interaction. Ideas of mathematical elegance have inspired, entranced, and "sometimes misled" thinkers in their desire to find the laws that govern our universe. Orrell evaluates these aesthetic principles as a means of understanding the structure of the universe - let alone messy human society - and questionswhether they reflect an accurate way to understand our world. Truth or Beauty comes at an interesting period, when the multi-billion-dollar Large Hadron Collider in Switzerland has been designed to test the existence of exotic phenomena such as supersymmetric particles. Will these too turn out to be nothing more than a beautiful illusion?